1. Field of the Invention
The present invention relates to a bag-making-and-filling packaging apparatus, and more specifically to improvement of delivering and registering systems of packaging material for a bag-making-and-filling packaging apparatus in which a web supplied from a roll of packaging material is formed into a tube through a tube-forming member and intermittently delivered and the formed tube is filled with a material to be packaged and when the filling is completed, the tube is sealed along the width thereof.
2. Description of the Prior Art
The conventional packaging apparatus comprises downstream of a tube-forming member delivery means, such as delivery belts or rollers, having a driving member and adapted for intermittent delivery by constantly rotating the driving member and then stopping it so as to obtain a predetermined length of delivery
In such a conventional system, however, slippage between the delivery belts or rollers and the packaging material, error in precision and control of mechanical components and others cause the delivered length different from a set length and fluctuation of delivery length.
In another prior art system as disclosed in Japanese Patent Publication No. 59-3325 (corresponding to U.S. Pat. No. 4,288,965), there is provided upstream of the tube-forming member a delivery roller which is adapted to deliver the web as well as to measure the delivery length.
In this prior art system, however, it is required to dispose downstream of the tube-forming member a delivery belt so as to keep the packaging material downstream of the delivery roller in the strained condition. Then, great load is applied to the belt, and at the same time, the system is designed to intentionally cause slippage between the belt and the packaging material, resulting in lowered durability of the belt and damage to the packaging material due to the slippage.
The above bag-making-and-filling packaging apparatus includes a registering system or, more in detail, system in which, when each of boundary portions of patterns, such as pictures, trademarks and indications, printed on the web of the packaging material at regular intervals corresponding to packaging length reaches the position of a sealing device, travel of the web is stopped. In this system, the web with register marks is supplied from a roll of packaging material and delivered to travel by delivery means, and there is provided on the web-travelling path a sensor for detecting the register marks, and the driving member of the delivery means is stopped when the sensor detects a register mark.
In such a prior art registering system, immediately after the sensor detects a register mark, the clutch of the driving member of the delivery means is disengaged to stop travel of the web, and if packaging materials having various register mark pitches are used, it is required to move the position of the register mark sensor along the web-travelling path through operation of a handle so as to adjust stop timing of the web.
If there is any positional shifting of patterns during operation using a packaging material, adjustment by moving the sensor is also required.
Thus, such a registering system not only requires much time for setting and adjustment, but also lacks in reproducibility, resulting in poor performance, and, furthermore, it has a defect that, as the sensor must include a moving structure, attachment structure of the sensor is complicated.